Operation Manual for - Mrclab.com

Ultrasonic milk analyzerAPPENDIX 8 CONDUCTIVITY MEASURING1. Method of determination.Conductivity (or Electrolytic Conductivity) is defined as the ability of asubstance to conduct electrical current. It is the reciprocal of the resistance.In a healthy animal*, the mean value of electric conductivity is:Milk typeCow milkSheep milkBuffaloConductivity valuesbetween 4 to 6 mS/cm (18°C);between 3 to 5 mS/cm (18°C);between 2,5 to 5 mS/cm (18°C);*These values depend on the geographical region, the breed and on otherfactors.Milk conductivity changes on the concentration of ions in the milk:Added water, sugar,proteins, insolublesolidsAdded saltsSignificantly extremevalue (6,5 - 13,00Decrease the ion's concentration. Milk conductivitydecreases.Increase the ion's concentration. Milk conductivityincreases. Increase the ion's concentration. Milkconductivity increases. Often the milk is falsifiedby adding salt: towards milk with goodcharacteristics: fat 4%, SNF 8,8, conductivity 4,5are added salt and water. Then the results arechanged to 3,2 and 8,8, conductivity 10. In otherwords adding water regulates the increased valueof SNF and density till normal (within theboundaries/parameters) and even the fat isnormal. By the values of these parameters may bedetermined if the sample is falsified, but the onlycharacteristic, proving this is conductivity, which isout of boundaries nevertheless added water. Butbe careful, as the falsification is not the onlypossible reason for conductivity increasing. Theother possibility is mastitis that’s why werecommend using another (chemical) method forchecking it.Should indicate the development of mastitis.Infections damage the tissue of the udder. ThisOperation manual 87/98